Projection of pictures in colors



June 17, 1941.

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June 7, 1941.

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UNITED STATES PATENT OFFICE PROJECTION OF PICTURES IN COLORS Otto C.Gilmore, Van Nuys, Cali1'., assignor to Cosmocolor Corporation, JerseyCity, N. 1., a

corporation of Delaware Application October 27, 1937, Serial No. 171,311

Claims.

This invention relates to the art of color photography and moreparticularly to the projection of moving pictures in color.Specifically, the present invention is concerned with the projection ofpictures in color from films upon which the color values of the scenesphotographed are represented in two or more black and white images lyingwithin a single frame.

Prior to the present invention a number of at; tempts have been made tofind a satisfactory means for projecting pictures in color from films ofthe type mentioned and these attempts are typically illustrated byPatent 1,262,954, granted to F. E. Ives in 1918, by Patent 1,350,143,granted to F. W. Donisthorpe in 1920, by Patent 1,631,866, granted toAnton Heurung in 1927, and by Patent 2,050,224, granted to the presentinventor in 1936. United States Patent No. 2,152,959 granted to thissame inventor, is also concerned with this same problem. A casualinspection of the patents mentioned will furnish a rather completehistory of the development of the particular type of device hereinvolved. 1

In the design of devices of the type to which the present inventionrelates many problems have been encountered. The projections from theseveral images on the film must be undistorted and of exactly the samesize and geometrical configuration when they reach the screen. They mustall focus at the screen and furthermore they must represent color valueswhich will combine to produce on the screen an accurate", and pleasingreproduction of the color of the original scene. The device used for theprojection must be relatively simple to adjust and sim-t ple inoperation and one that does not absorb or tended for the screen. Thisinventor has discovered that in order to obtain ready acceptance of hisprocess it is also highly desirable that his device be in the form of anattachment which can be readily inserted in the ordinary theatreprojector in place of the ordinary projection lens.

By the arrangement of parts hereinafter dewhich, in addition, can bequickly and easily substituted for the ordinary projector lens in thetheatre projectors now in common use.

The basic elements of the optical system of the device of the presentinvention are the same as those described in this inventors UnitedStates Patent No. 2,152,959; that is, they comprise from the filmtowards the screen in the order named, a completely separate objectiveand color filter for each of the images on the film and a turning prismmeans. The latter may be a separate prism for each image on the film ora single prism which turns all of the images. By the use of a completelyseparate objective lens for each of the images, the problem of focusingand registering has been found to be greatly simplified and the passageof stray light from one image pencil into the other in the lens set hasbeen entirely eliminated. The elimination of other parts of the opticalsystem, which this inventor has found unnecessary, adds greatly to theefficiency of the system and to the sharpness, clarity and brightness ofthe projected pictures.

The color filters may be placed on either side of the objective lensesor between the elements of these lenses. A part of this inventionresides in the discovery of a particular combination of colors, whichwhen used in these color filters will produce exceptional and unusuallygood results in the projected pictures. When projecting from a filmhaving tw images to the frame, filters corresponding to Wratten filterNo. 28, cine red, and Wratten filter No. 38, toluidine blue, have beenfound to be far superior to pictures projected through any othercombination of filters known to this inventor. The picture projectedthrough 'the No. 28 filter should preferably have been taken through afilter similar to a Wratten No. 22 red filter and the image projectedthrough the No. 38 filter should have been taken through a filtercorresponding to a Wratten filter No. 59, projection green, if taken insunlight, a Wratten filter No, 59A, projection green (light), if takenin incandescent light, and a No. 60? Wratten filter if taken in arelight.

Although the filters may be in the form of a gelatin film cementedbetween optical glass, it has been found preferable to use heatresisting Corning glass of the same color. In projection, the heatgenerated by the source of light is so great that gelatin film filtersare likely to be injured.

Another improvement in the present device is found in the manner inwhich the objectives are mounted. As shown in United States Patent No.2,152,959, both objectives are shiftable in a plane normal to the lightbeam. It has now been found that by definitely fixing the position ofone of the two objectives and making the other objective movable in twodirections in the plane normal to the light beam, 9. definite advantageresultse The objective that is permanently fixed is, of course, placeddirectly in front of and in line with the image that it is to focus onthe screen. Being fixed, it remains in this position and there is nopossibility of adjusting it to a position where it will not be incorrect alignment and cause distortion. The movable objective, beingadjusted so as to cause its image to register with the image of thefixed objective, is necessarily adjusted at all times to about the sameposition, and never has an opportunity to get very much out of line withthe image on the film.

Another feature of. the present invention is the arrangement by whichthe light from the two separate images is prevented from diffusing fromone image bearing light pencil into the other during the passage of thelight pencils from the images on the film through theobjective lenses.This arrangement includes completely separate objective lens systems andother structural arrangements. The completely separate lens systernshave the added advantage of permitting the lens systems to beindividually positioned and advantage has been taken of this fact toposition the lens systems differently so as to compensate for thedifference in the color of the light which they focus on the screen. Inother words since blue is refracted to a greater extent than red thelens system for the blue is positioned farther from the film to causethe blue image to focus in the same plane as the red.

The arrangement which completely separates the light beams alsocomprises a telescopic hood mounted in the rear end of the main housingand resiliently pressed towards the film gate of the projector. It alsoincludes a septum or a dividing fin mounted in the telescopic hood so asto extend from the film gate forward to a position between the objectivelenses. At this point the septum cooperates with diaphragms oradditional septums which cover the adjacent sides of the objective lenssystems and form between them a slot in which the end of the movableseptum may slide. The movable septum is slightly warped so as tocompletely fill the slot and because of this arrangement no light canpass through the slot and into the turning prism, or from one light beaminto the objective intended for the other light beam.

A still fLu'ther improvement that it has been found desirable toincorporate in the present device is a series of baffles which surroundthe path of the image bearing light beams between the objectives and theturning prism means. These baflles act to intercept any stray light fromthe objectives and absorb or turn it back so that it cannot enter theturning prism.

Besides these improvements the present invention also includes means forquickly and easily positioning the new lens system in place of the usualprojection lens, in two of the more common types of projection machines.At the present time, many theatres are equipped with a type of projectorknown as the Standard Simplex projector manufactured by theInternational Projector Corporation. In order to replace the projectionlens in such a projector by the lens system of this invention, it isnecessary to loosen the lens clamp, remove the lens, place the new lensdevice in the clamp, adjust it to the desired position, and tighten theclamp. This seems simple enough, but in practice it is quite difiicultto accomplish because the new lens system must be positioned, axially,just far enough in the projector so that it will be substantially infocus,

and at the same time the new lens system must be rotated about its axisto a position where the base of the turning prism will be at an angleoi. exactly 45 to the horizontal so that it will act properly to turnthe images into their upright position. In order to provide a means foraccomplishing this positioning with a minimum loss of time and withmaximum accuracy, the present invention provides means mounted on thehousing of the projector and additional means mounted on the lensattachment which are engaged when the device is first placed in theprojector and serve to position the device accurately. These means arethen released from their engagement so that the normal focusingmechanism of the projector can make the final adjustment to bring thepicture to maximum sharpness on the screen.

Another type of projector that is now in extended commercial use isknown as the Super Simplex projector. This projector is likewisemanufactured by the International Projector Corp. The present inventionalso includes an arrangement of parts by which the optical system ofthis invention may be inserted into this type of projector with the samecase and certainty as the arrangement already mentioned provides in thecase of the Standard Simplex projector. The arrangement of parts in thecase of the Super Simplex projector includes an outer shell whichsurrounds the main housing of the device of. this invention. This shellis of such a size that it may be readily clamped in the two lens clampsof the projector. At the forward end of this shell is a positioning ringso constructed as to clamp tightly onto the shell and cooperate withparts already present on the projector to accurately position the devicein the lens clamps.

Other improvements embodied in the present invention will be apparentfrom the appended drawings and the following detailed description of thespecific embodiments of this invention shown in the drawings.

In the drawings:

Fig. 1 is a side view of a part of a Standard Simplex projector, partlycut away to show the device of the present invention in place therein;

Fig. 2 is a front view of the same part of a projector that is shown inFig. 1;

Fig. 3 is a rear end view of the device of this invention, showing thetelescopic hood that cooperates with the film gate of the projector;

Fig. 4 is a partial side view of the device of this invention, takenalong the line 4-4 of Fig. 3, partially in section so as to show thearrangement of the objective lenses and the telescoping hood;

Fig. 5 is a sectional view of the remainder of the device of thisinvention taken on line 5-5 of Fig. 2;

Fig. 6 is a bottom sectional view of the part of the device shown inFig. 5, the section being taken along the line 6-6 of Fig. 5;

Fig. 7 is a sectional view of the device of. this invention taken alongthe line 1-1 of Fig. 4 and looking toward the forward end of the device;

Fig. 8 is a top sectional view of the same part of the device as isshown in Fig. 4, taken along the line 8-8 of Fig. 4 and showing thetelescoping liood pressed further into the housing than in Fig. 4;

Fig, 9 is an axial section of the device taken on line 9-9 of Fig. 5 andlooking toward the rear of the device;

Fig. 1.0 is a similar view taken on line III-I6 of Fig. 1;

Fig. 11 is a similar view taken on line I l-ll of Fig. 4;

Figs. 12, 13 and 14 together constitute an expanded view of the interiorparts of the device;

Fig. 15 is a sectional detail view of the device shown in Fig. and istaken along the line l5--I5 of that figure, looking in an axialdirection toward the rear of the device;

Fig. 16 is a side view of a part of a Super Simplex projector, parts ofwhich have been cut away to show a device embodying the principles ofthe present invention in place therein;

Fig. 17 is a front view of the same part of a projector as shown in Fig.16;

Fig. 18 is a partial side view partially in section of the modificationof the device of the pressent invention which is suitable for use in aSuper Simplex projector and is taken along line |8-l8 of Fig. 1'1. Thisfigure also shows a part of the projector clamps of the projector in theposition that they occupy when the device of the present invention is inplace in a projector;

Fig. 19 is a bottom view of a part of the device shown in Fig. 18, withparts cut away to show the arrangement of the objective adjusting rods.It has been taken along line 19-49 of Fig. 17;

Fig. 20 is an axial sectional view taken along the line 20-20 of Fig. 18and looking toward the rear of the device;

Fig. 21 is a spectrophotometric absorption curve of a #28 Cine RedWratten filter;

Fig. 22 is a similar curve for a #38 Toluidine Blue Wratten filter;

Fig. 23 is a similar curve for a #22E2 Red Wratten filter;

Fig. 24 is a similar curve for a #59 Projection Green Wratten filter;

Fig. 25 is a similar curve for a #59A Projection Green (light) Wrattenfilter;

Fig. 26 is a similar curve for a #BOP Wratten filter.

As shown by the drawings, and particularly by Figs. 4 and 5, light fromthe projection light in the projector, after passing through a filmwhich has two images within each frame, enters the device of thisinvention through the opening 30 in the telescopic hood 3|. This hood istelescopically mounted in a cylindrically shaped main casing 32 and isguided by rods 33 and 34 which are fixed rigidly in the lens support 35which in turn is fastened to the main housing 32. The guide rods 33 and34 are received in sleeves 36 and 31 rigidly fixed in the telescopichood and coil springs 39 and 39 surround the rods and sleeves, bearingagainst the hood on one end and the main lens support 35 on the other,so as to press the hood outward against the film gate of the projector.As can be seen from Fig. 8, a cap screw 40 in the side of the hood 3|cooperates with a slot 4| in the main housing to limit the movement ofthe hood with respect to the housing so that this device will not comeapart when it is removed from the projector. In addition, a part of thetelescopic hood is cut away and covered with a small plate 42 afflxedwith screws 43 so as to avoid interference with the mechanism of theprojector.

Upon entering the device shown in the drawings, the beams or pencils oflight proceed directly to their respective objective lens systems 44 and45. Each of these lens systems includes a pair of compound lenses 46 anda color filter 41. The lenses of each set are mounted in primarycarrying members 46. The lenses are held in placeJn the primary carryingmembers by retaining rings 49 and 50, the ring 56 being toward the rearof the device and having the color filter mounted in it. A sub-retainingring 5| functions to hold the color filter in the lens retaining ring50.

The primary carrying members 48 and the retaining rings 49 and 50 extendonly part way around the lenses and leave the adjacent sides of the twoobjective lens systems, 44 and 45, exposed. These sides are covered bydiaphragms or septums 52 and 53 so as to prevent the diffusion of lightfrom one objective lens set into the other. As an additionalpreventative against the diffusion of light from one light beam into theother, a septum 54 is mounted in the telescopic hood and extends fromthe entrance to the hood to a point well between the diaphragms 52 and53. The septum 54 is slightly warped at the place where it extendsbetween the diaphragms so that it will at all times tightly close thegap between the diaphragms and seal this gap so that no light can passthrough it.

As shown in Fig. 4, one of the primary lens carriers is mounted directlyand rigidly fixed in the main lens support 35. This objective nevermoves relative to the main housing of the device. The other primary lenscarrier, however, is mounted in a movable carrier 55 which is in turnslidably mounted on a transversely movable member 56, which again inturn is slidably mounted on the prism retaining frame 51, which is fixedto the main housing 32 by screws 51a. The slidable mounting in each caseis of the tongue and groove type and the mountings are so arranged thatthe transversely movable member 56 can slide transversely on the prismretaining member 51, carrying with it the movable lens mounting 55,which can also slide on the member 56 and move vertically with respectthereto.

In order to actuate the transversely movable member and the movable lenscarrier, rods 53 and 59, shown in Figs. 13 and 14 are provided, the rodscarrying eccentrically mounted hardened rollers 69 and 6| on theirrearwardly extending ends and short levers 62 and 63 on their forwardends. The rod 59 is rotatably mounted in an opening 64 in the prismretaining frame 51 so that the hardened roller 6| will enter a slot 65in the transversely movable member and will operate upon rotation of therod to shift that member in a transverse direction. The rod 53 ismounted in another opening 66 in the prism retaining frame 51, and isalso free for rotation. This rod passes through an opening 61 in thetransversely movable member 56 and the roller 69 on this rod engages aslot 68 in the movable lens carrier 55. Upon rotation of the rod 56 theroller 60 acts to move the movable lens carrier 55 in a verticaldirection.

In order to maintain the movable members 55 and 56 against the prismretaining ring 51, a spring retaining ring 69 has been provided as shownin Fig. 5. This ring is fastened by screws 16 to the main lens support35 and presses against the movable lens carrier 55.

From the objective lens system, the two beams or pencils of light passthrough an opening 1| in the prism retaining frame and to a dove prism12. The edges of the opening 1| are of a sawtooth cross section with thepoints directed rearwardly so as to form a series of bailles 12a whichcatch any stray light that passes through the objective lens system andeither absorb this light or reflect it back and away from the prism. The

prism retaining frame 51 is so constructed as to hold one of the lowercomers of the prism and also, with the help of a cork retaining memberI3, a washer I4 and a screw I5 holding these members to the frame, tohold in position the upper corner of the prism. In addition, the prismretaining ring 51 includes a hood member I6 which surrounds the incominglight beams and prevents light which may be reflected from the face ofthe prism from diffusing around the prism. The other lower corner of theprism is supported by a supporting member 11 attached to the mainhousing 32 by a pin 18 and screws 19.

In the embodiment of the new device that is adapted to fit into aStandard Simplex projector, a cap 88 of the type shown in Figs. 5 and 6covers the forward end of the main housing 32. This cap which is held inplace by screws 8| has an opening 82 through which the image-bearinglight pencils pass to the screen, and also has two smaller openings 83and 84 which receive the forward end of adjusting rods 58 and 59respectively.

In order to prevent the adjustment of the device from changing after ithas been set, a brake is provided for the two adjusting rods as shown inFigs. 5, 6 and 10. This brake consists of a cross bar 85 through whichboth of the adjusting rods 58 and 59 pass. A screw 89 connects the crossbar to the cap 88, and when this screw is tightened the cross bar isdrawn toward the cap so as to bear tightly against the levers 62 and 63on the adjusting rods.

The arrangement whereby this device may be readily mounted on a StandardSimplex projector consists of an annular member 81 which takes the placeof the annular member which ordinarily surrounds the lens opening in thefront of the projector. The annular member used according to thisinvention however carries a forwardly extending lug 88 which is arrangedto engage and position a ring shaped clamping member 89 which ispermanently mounted on the new projection device by means of bolts 98which span a split side of the ring. The ring is so designed as to havean outwardly extending arm 9| shaped so as to receive the end of thepositioning lug 88 and a thumb screw 92 is carried by this arm andreceived in a threaded opening in the lug 88 so as to clamp the arm inposition against the lug. In this position, the lug 88 partially entersa recess in the arm so that the position of the ring 89 and the newprojection device is accurately fixed. To hold the bolt 92 at all timesin the upper position in the arm 9|, a spring 93 is provided within theopening in the arm through which the bolt passes. This spring surroundsa part of the bolt and one end presses against the arm while the otherpresses against a small retaining ring 94 affixed to the bolt. In thismanner, the spring constantly urges the bolt further into the opening inthe arm so that the head of the bolt is kept constantly against the arm.The bolt, however, is free to move yieldably when the arm is against thepositioning lug.

As can be seen from Fig. 1 this positioning lug is preferablyconstructed separately from the annular member 81 and is connectedthereto by means of a pin 95 which passes through the positioning lug 88and also through two small lugs 96 which are part of the annular memberand one of which lies on each side of the positioning lug. The part ofthe arm 9| which is immediately in contact with the positioning lug isalso made separately from the remainder of the arm and as shown in Fig.1 is merely pressed tightly into an opening in the arm.

In operation. the device of the present inven-- tion is placed in theprojector from the front end andmoVes axially toward the rear until thebolt 92 engages the annulus 81 through its positioning lug 88 and thearm 9| on the ring. The bolt 92 is then tightened in the lug 88 and thedevice is in its initial position in the projector. The projector clamp91, shown in Fig. 1, is then tightened 0n the housing 32 and the bolt 92loosened to permit focusing adjustments of said device. The device isnow ready for operation. Adjustment may be made to register the image onthe screen by moving the small levers 62 and 93 and final focusing maybe accomplished by the usual focusing mechanism of the projector.

When the device of the present invention is to be used with a SuperSimplex projector, the cap 88 is replaced by an adapter shell 98 whichencloses the whole forward end of the main housing 32 and extendsforward for a short distance beyond the housing. It is connected to thehousing by bolts 98a. The adjusting rods 58 and 59 are somewhat longerthan they are in the model already described but are received in theadapter shell in much the same manner that they are in the cap 88 andcarry similar levers on their forward ends. A plate 99 fastened to theadapter shell by screws I88, I8I and I82 serves as a brake to preventaccidental rotation of the shafts. The screw |8I acts to draw this platedown tightly against the ends of the rods to prevent movement.

A positioning ring |83 is clamped around the adapter shell nearest theforward end by means of a thumb screw I84 spanning a split side. Thisring carries an arm I which cooperates with a forwardly extending shaftI88 already on the projector and also has an opening I81 which fits overa forwardly extending shaft I88 also already a part of the projector. Bymeans of these two arrangementsgthe rotative position of the new opticalsystem is accurately fixed, and the ring'I83 is so placed on the shellthat the axial position of the device will be fixed by pressing thedevice back into the projector until the ring I83 rests against theforward lens holding clamp I89 of the projector. Once the device is inthis position both the forward clamp I89 and a rear clamp 8 aretightened on the device and final adjustment may be made by the usualfocusing mechanism and the small registering levers 62 and 53.

While the particular constructions which make the present device readilyadaptable for use with two of the most commonly used projectors aredefinitely a part of this invention, it is to be understood that theprinciples of the invention may be applied more broadly and that theinvention is therefore not limited to this particular embodiment.

I claim:

1. In a device for projecting two pictures in superposed relation upon ascreen, from a film on which the two pictures appear in side by siderelation and on their sides within a single frame, the combination oftwo completely separate objective lens systems, one for each image.erecting prism means for turning both images into their uprightpositions, and baffles surrounding the path of the light beams betweenthe objective lens system and the erecting prism means, said baillesbeing arranged to prevent the passing of stray light from the lenssystems to the erecting prism means.

2. A device for projecting pictures in color from black and white filmscarrying color records that comprises two completely separate objectivelens systems arranged to project images from two separate records, colorfilters positioned so as to filter the light that passes through each ofsaid objective lens systems, means for holding one of the objective lenssystems in a fixed position, and means for shifting the other objectivelens system in a plane normal to the light passing therethrough and intwo directions substantially at right angles to each other, erectingprism means for turning both images into their upright positions,baiiles surrounding the path of the light beams from the records betweenthe objective lens systems and the erecting prism means, said baiiiesbeing arranged to prevent the passing of stray light from the lenssystems to the erecting prism means, a mask for each objective lenssystem positioned along the side of the lens system which lies adjacentthe other lens system so as to completely shield its lens system againstthe entrance of stray light from the other system, an axially movableseptum arranged to extend from a point close to the film to a pointbetween the masks and completely separate the light beams from therespective records, said septum being slightly warped at a point betweenth masks so as to :ompletely close the slot between them and allow nolight to pass therethrough, a cylindrical housing for said parts, apositioning means associated with said housing and arranged so as tocooperate with parts of a standard type of motion picture projector tolocate the parts within said housing in a predetermined position withrespect to said projector, and means to secure said housing in saidpredetermined position to the casing of the projector.

3. In a projection device the combination of two completely separateobjective lens systems, a mask for each objective lens system positionedalong the side of the lens system which lies adjacent the other lenssystem, so as to completely shield its lens system against the entranceof stray light from the other system, a housing to enclose said parts, ahood telescopically mounted on said housing means for resiliently urgingsaid hood from said housing, and an axially movable septum supported bysaid hood and arranged to extend from a point close to the film to apoint between the masks and completely separate the light beams from therespective pictures.

4. A device for projecting a pair of images which are carried by asupport on to a screen in registration, comprising a housing, a separateobjective system for focusing each image upon the screen, a prism meansfor turning the images separate supports within said housing for saidobjective systems and said prism means, said prism support beingprovided with a series of bailies to prevent the passing oi! stray lightto said prism means, one of said objective systems being mounted in afixed support, the other of said objective systems being mounted withina movable support, shields carried by said objective supports to preventthe diffusion of light between said systems, a telescopic hood supportedby said housing and arranged to resiliently extend from said housingtoward said film, and an axially movable septum supported by said hoodand arranged to extend between said shields to prevent the diffusion oflight from one image beam into another, said septum being bent at apoint between the shields so as to resiliently close the slottherebetween regardless of the distance between said shields and therebyprevent the passing of stray light to said prism means.

5. A device for projecting images which are carried by a transparency ontheir sides on to a screen in registration, a housing, a separateobjective system for focusing each image upon the screen, prism meansfor erecting said images during projection, separate supports withinsaid housing for said objective systems and said prism means, said prismsupport being arranged to locate said prism means in a predeterminedposition within said housing, one of said objective systems beingmounted in a fixed support, the other of said objective systems beingmounted within a movable support, means carried by said prism support tocontrol the adjustment of said movable objective support whereby toadjust said objective system with respect to its companion objectivesystem and to said prism means, and positioning means carried by saidhousing and arranged to cooperate with parts of a standard type ofmotion picture projector to locate said housing in a predeterminedposition with respect to said projector.

6. A device for projecting a pair of images which are carried by atransparency on their sides on to a screen in registration, a housing, aseparate objective system for focusing each image upon the screen, aprism means for erecting said images during projection, separatesupports within said housing for said objective systems and said prismmeans, said support for said prism means being arranged to locate saidprism means in a predetermined position within said housing, one of saidobjective systems being mounted in a-support fixed to said prism supportto locate said objective in a predetermined position with respect tosaid prism means, the other of said objective systems being mountedwithin a movable support carried by said prism support, means carried bysaid prism support to control the adjustment of said movable objectivesupport whereby to adjust said objective system with respect to itscompanion objective system and to said prism means.

7. A device for projecting a pair of images which are carried by atransparency on their sides on to a screen in registration, a. housing,a separate objective system for focusing each image upon the screen, aprism means for erecting said images during projection, separatesupports within said housing. for said objective systems and said prismmeans, said support for said prism means being arranged to locate saidprism means in a predetermined position within said housing andincluding a series 01' baiiles to prevent the passing of stray light tosaid prism means, one of said objective systems being mounted in asupport fixed to said prism support to locate said objective in apredetermined position with respect to said prism means, the other ofsaid objective systems being mounted within a movable support carried bysaid prism support, means carried by said prism support to control theadjustment of said movable objective support whereby to adjust saidobjective system with respect to its companion objective system and tosaid prism means, shields carried by said objective supports to preventthe difiusion oi! light between said systems, a telescopic hoodsupported by said housing and arranged to resiliently extend from saidhousing toward said film, an axially movable septum supported by saidhood and arranged to extend between said shields to prevent thediffusion of light from one image beam into the other, said septum beingbent at a point between the shields so as to resiliently close the slottherebetween regardless of the distance between said shields and therebyprevent the diffusion of light to said prism means, positioning meanscarried by said housing and arranged to cooperate with parts of astandard type of motion picture projector to locate said housing in apredetermined position with respect to said projector, and clampingmeans to secure said housing thereto in said predetermined position.

8. A device for projecting images in pairs comprising an apparatus forhandling film, two completely separate objective lens systems, one foreach image beam, erecting prism means for turning both image beams oneof said objective lens systems being movably mounted to permitdifferential adjustment with respect to the other objective lens system,a mask for each objective lens system to prevent the diffusion of lightbetween the systems, and a septum arranged to extend from a point closeto the film to a point between the masks to prevent diffusion betweenthe image beams, said septum being bent at a point between the masks soas to resiliently bear against the opposed surfaces of said masks andclose the space between the masks regardless of the distancetherebetween and thereby prevent the passing of stray light through saidspace to said prism means.

9. In a device for projecting two pictures in superposed relation upon ascreen, from a film on which the two pictures appear in side by siderelation and on their sides within a single frame, the combination oftwo completely separate objective lens systems, one for each image,erecting prism means for turning both images into their uprightpositions, a support for said prism, and baflles carried by said prismsupport and surrounding the path of the light beams be tween theobjective lens systems and the erecting prism means, said baiiies beingarranged to prevent the passing of stray light from the lens systems tothe erecting prism means.

10. In a projection device the combination of two completely separateobjective lens systems,

a mask for each objective lens system positioned along the side of thelens system which lies adjacent the other lens system, so as tocompletely shield its lens system against the entrance of stray lightfrom the other system, a housing to enclose said parts, a hoodtelescopically mounted on said housing, cooperating guide means carriedby said housing and said hood, resilient means located by said guidemeans for urging said hood from said housing, and a septum carried bysaid hood to extend from a point close to the film to a point betweenthe masks and completely separate the light beams.

11. In a projection device the combination of two completely separateobjective lens systems, a mask for each objective lens system positionedalong the side of the lens system which lies ad- J'acent the other lenssystem, so as to completely shield its lens system against the entranceof stray light from the other system, a, housing to enclose said parts,guide rods mounted on said housing, a hood telescopically mounted onsaid housing, guide sleeves carried by said hood for telescopicallyreceiving said guide rods, helical springs surrounding said guidesleeves and guide rods for resiliently urging said hood from saidhousing, and a septum carried by said hood to extend from a point closeto the film to a point between the masks and completely separate thelight beams.

12. A device for projecting images which are carried by a transparencyon their sides on to a screen in registration, a housing, separateobjective systems for focusing said images upon the screen, prism meansfor erecting said images during projection, separate supports withinsaid housing for said objective systems and said prism means, said prismsupport being arranged to locate said prism means in a predeterminedposition within said housing, one of said objective systems beingmounted in a fixed support, the other of said objective systems beingmounted within a movable support, and means carried by said prismsupport to control the adjustment of said movable objective supportwhereby to adjust said objective system with respect to its companionobjective system and to said prism means.

13. A device for projecting a pair of images which are carried by atransparency on their sides on to a screen in registration, a housing,separate objective systems for focusing each image upon the screen, aprism means for erecting said images during projection, separatesupports within said housing for said objective systems and said prismmeans, said support for said prism means being arranged to locate saidprism means in a predetermined position within said housing, one of saidobjective systems being mounted in a support fixed to said prism supportto locate said objective in a predetermined position with respect tosaid prism means, the other of said objective systems being mountedwithin a support which is movably mounted on said prism support,adjusting means carried by said prism support whereby to adjust saidobjective system with respect to its companion objec tive system and tosaid prism means, and means carried by said housing for locking saidadjusting means to retain the movable objective system in adjustedposition.

14. A projection device comprising a photographic apparatus having a lugextending therefrom, two separate objective systems and a turning prismmeans with a housing therefor, the parts of said optical system beingmounted in predetermined positions in said housing, and an arm mountedon said housing in a predetermined position, said arm having a dishedportion which is adapted to fit over the lug carried by saidphotographic apparatus for positioning said housing with respectthereto, a threaded bore extending into said lug, and a bolt mounted onsaid arm and adapted to be threaded into the bore of said lug to securesaid arm to said lug.

15. A projection device comprising a photographic apparatus having a lugextending therefrom, a threaded bore extending into said lug, twoseparate objective systems and a turning prism means with a housingtherefor, the parts of said optical system being mounted inpredetermined positions in said housing, and an arm mounted on saidhousing in a predetermined position, said arm having a dished portionwhich is adapted to fit over the lug carried by said photographicapparatus for positioning said housing with respect thereto, and a boltmounted on said arm, means to yieldingly urge said bolt toward said lug,being thereby adapted to be threaded into the bore of said lug to securesaid arm to said lug.

16. In a device for projecting two pictures in superposed relation upona screen, from a film on which the two pictures appear in pairs, thecombination of two completely separate objective lens systems, one foreach image, two color filters, one for each of said lens systems, one ofsaid filters having substantially the same color as a Wratten filter No.28 and the other of said filters having substantially the same color asa Wratten filter No. 38, erecting prism means for turning both imagesinto their upright positions, a mask for each objective lens systempositioned along the side thereof which lies adjacent the other lenssystem, and a septum positioned so as to extend from a point close tothe film to a point between the masks and thereby completely separatethe image means, said septum being bent at a point between the masks soas to resiliently bear against the opposed surfaces of said masks andclose the space therebetween to prevent light from passing therethroughto said prism means, and means to mount said septum for axial movement.

17. In a projection device the combination of two completely separateobjective lens systems, means for mounting one of said objective lenssystems in a fixed position, means for mounting the other of saidobjective lens system for movement in a plane normal to the lightpassing therethrough, eccentric cam means for shifting the movableobjective system in two directions substantially at right angles to eachother, and clamping means in engagement with said cam shifting means forsecuring said shifting means in adjusted position whereby to retain saidobjective lens system in adjusted position.

18. A device for projecting a pair of images which are carried by atransparency on their sides on to a screen in registration, a housing,separate objective systems for focusing each image upon the screen,prism means for erecting said images during projection, separatesupports within said housing for said objective systems and said prismmeans, said support for said prism means being arranged to locate saidprism means in a predetermined position within said housing, one of saidobjective systems being mounted in a support fixed to said prism supportto locate said objective in a predetermined position with respect tosaid prism means, the other of said objective systems being mountedwithin a support, means to mount said objective support for slidablemovement in one plane upon a carriage, means to mount said carriage forslidable movement in another plane on said prism support, said planeslying at right angles, and adjusting means carried by said prism supportwhereby to adjust said objective system with respect to its companionobjective system and to said prism means.

19. A device for projecting a pair of images which are carried by atransparency on their sides on to a screen in registration, a housing,separate objective systems for focusing each image upon the screen,prism means for erecting said images during projection, separatesupports within said housing for said objective systems and said prismmeans, said support for said prism means being arranged to locate saidprism means in a predetermined position within said housing, one of saidob ective systems being mounted in a support fixed to said prism supportto locate said objective in a predetermined position with respect tosaid prism means, the other of said objective systems being mountedwithin a support, means to mount said objective support for slidablemovement in one plane upon a carriage, means to mount said carriage forslidable movement in anotner plane on said prism support, said planeslying at right angles, one adjusting means carried by said prism supportand connected with said objective support whereby to adjust saidobjective system in said one plane with respect to its companionobjective system and to said carriage and prism means, and a secondadjusting means carried by said prism support and connected with saidcarriage whereby to adjust said carriage and said objective system insaid other plane with respect to its companion objective system and tosaid prism means.

20. A device for projecting a pair of images which are carried by atransparency on their sides on to a screen in registration, a housing,separate objective systems for focusing each image upon the screen,prism means for erecting said images during projection, separatesupports within said housing for said objective systems and said prismmeans, said support for said prism means being arranged to locate saidprism means in a predetermined position within said housing, one of saidobjective systems being mounted in a support fixed to said prism supportto locate said objective in a predetermined position with respect tosaid prism means, the other of said objective systems being mountedwithin a support, means to mount said objective support for slidablemovement in one plane upon a carriage, means to mount said carriage forslidable movement in another plane on said prism support, said planeslying at right angles, one adjusting means carried by said prism supportand connected with said objective support whereby to adjust saidobjective system in said one plane with respect to its companionobjective system and to said carriage and prism means, a secondadjusting means carried by said prism support and connected with saidcarriage whereby to adjust said carriage and said objective system insaid other plane with respect to its companion objective system and tosaid prism means, and means carried by said housing for locking both ofsaid adjusting means to retain the movable objective system in adjustedposition.

OTTO C. GILMORE.

